Restore Smooth Shifting to Your Buick LaCrosse
If you’re dealing with the frustration of a Buick LaCrosse that shifts harshly, gets stuck in gear, or throws transmission-related trouble codes, you’ve come to the right place. As a technician with over two decades of experience, I’ve seen countless drivers perplexed by these exact issues. Often, the culprit isn’t a catastrophic transmission failure, but rather a faulty Transmission Control Module (TCM)—the electronic brain that manages every shift. This replacement T42 TCM, part number 24241806, is the definitive solution for your 2006-2009 LaCrosse TCM problems, arriving pre-programmed for a hassle-free installation.
A Technician’s Notebook: The Misleading P0700 Code
A customer brought in his 2008 Buick LaCrosse with the check engine light on and complaints of it “banging” into gear. The initial scan showed a P0700 code, which is just a general fault request from the TCM. Digging deeper, we found intermittent solenoid circuit codes that would come and go. Instead of shotgunning expensive solenoids, we checked the TCM connectors for corrosion—they were clean. Experience told me this pointed to an internal failure in the module itself, likely from years of heat cycles under the hood. We installed a VIN-programmed TCM, cleared the codes, and the car shifted like it just rolled off the factory floor. This simple swap saved the customer from a potential transmission rebuild.
Is Your LaCrosse Exhibiting These Transmission Issues?
A failing TCM can manifest in several ways, often mimicking more severe mechanical problems. Before you assume the worst, check if your vehicle is showing any of these classic signs of a bad module. A new 2006-2009 LaCrosse TCM is often the fix.
- ✔ Abrupt, hard, or jerky gear shifts.
- ✔ The vehicle feels stuck in one gear (often called “limp mode”).
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
- ✔ Check Engine Light or Transmission Warning Light illuminated with codes like P0700, P0750, P0753, or other solenoid-specific DTCs.
- ✔ Unexplained drop in fuel economy.
- ✔ Complete loss of communication with the transmission module.
Plug-and-Play Installation: Your LaCrosse TCM Swap
One of the biggest benefits of this module is that it arrives ready to install, with no need for an expensive trip to the dealership for programming. For the 2006-2009 Buick LaCrosse, the TCM is located under the lower air cleaner housing, making it accessible for a seasoned DIYer or any professional mechanic. The entire process typically takes less than an hour.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and help reset the system.
- Locate the Module: On your LaCrosse, you will need to access the area beneath the air cleaner box to find the old TCM.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old module. Then, unbolt the module from its mounting bracket and remove it from the vehicle.
- Install the New TCM: Mount the new, pre-programmed TCM in the same location. Securely reconnect the electrical harnesses, ensuring they click into place.
- Final Steps: Reconnect the battery terminal. Start the vehicle and use a standard OBD2 scan tool to clear any stored diagnostic trouble codes. Take the car for a test drive to confirm the shifting issues are resolved.
Verified Fitment for Your General Motors Vehicle
While this is the perfect solution for your 2006-2009 LaCrosse TCM, this versatile T42 module is also compatible with a wide array of other GM vehicles. It directly interchanges with part numbers such as 24252114, 24234503, 24240400, and more. Please verify your specific model in the list below.
Partial Fitment List:
- Buick Allure (2006-2009) – lower air cleaner housing
- Buick LaCrosse (2006-2009) – lower air cleaner housing
- Chevrolet Impala (2006-2011) – lower air cleaner housing
- Chevrolet Monte Carlo (2006-2007) – lower air cleaner housing
- Pontiac Grand Prix (2006-2008) – lower air cleaner housing
- Chevrolet Silverado / GMC Sierra 1500 (2007-2013) – next to battery
- Chevrolet Tahoe / GMC Yukon (2007-2009) – next to battery
- …and many more GM models.
Frequently Asked Questions
What exactly is VIN programming?
VIN programming means we load your vehicle’s specific Vehicle Identification Number (VIN) and the latest GM software onto the module before shipping it. This ensures it communicates perfectly with your car’s other computers (like the ECU) for optimal shift patterns and performance, eliminating the need for dealer programming.
Do I need any special tools for this installation?
No special tools are required. Basic hand tools like a socket set and screwdrivers to access the air cleaner housing and unbolt the module are all you should need. An OBD2 scanner is recommended to clear codes after installation.
Will this fix a P0700 trouble code?
A P0700 code is a general alert from the TCM telling the main computer that a transmission fault exists. While a faulty TCM is a common cause, this code can also be triggered by other issues. However, if P0700 is present along with other TCM-specific or solenoid codes, replacing the module is a very likely fix.
Is there a core charge for my old part?
No, there is no core charge. You can keep your old module or dispose of it at your convenience, making the process simpler and more affordable.
What is the warranty on this TCM?
This transmission control module comes with a one-year warranty, giving you peace of mind and confidence in your repair.